Japanese Patent Application Laid-open Publication No. 2012-185076 discloses a speed limit value notification device which is capable of using both a traffic sign detected from an image picked up by a vehicle-mounted cameral and a traffic sign acquired from map data stored in a map data storage section.
However, the speed limit value notification device disclosed in the No. 2012-185076 publication cannot notify an occupant of a vehicle of a final traffic sign when the traffic sign based on the picked-up image and the traffic sign based on the map data do not agree with, or match, each other. In other words, the speed limit value notification device disclosed in the No. 2012-185076 publication merely presupposes that the traffic signs based on the map data have a high reliability. Thus, the inventors of the present invention etc. realized that, when the traffic signs based on the map data have a low reliability, the speed limit value notification device disclosed in the No. 2012-185076 publication can notify the vehicle occupant of final traffic signs only from a short time period.